They will have added colouring to cocoa butter (which is easier to colour than chocolate) and flicked that through the empty moulds like paint. That’s where the black and yellow splashes on the chocolates come from. Set that.

Then they’d have a supply of tempered chocolate ready, which they pour into the moulds on top of the “paint”. If they turn the moulds upside down so the liquid chocolate runs out, they’re left with a shell of chocolate in the moulds. Set that.

They fill that shell with ganache or whatever else they wanted to put inside, set that and cap it with another layer of tempered chocolate to form the flat base.

Five minutes in the blast chiller makes the chocolate base set. When they take the moulds out of the chiller, turn them upside down and tap them, finished chocolates come out. Tempering the chocolate is the necessary step which makes sure that it sets glossy and smooth like that, and gives it that nice clean snap when it breaks. It’s a useful skill for anyone who ever uses chocolate much to have.